This invention is related to U.S. Pat. No. 4,683,763 to V. Balter (1987), entitled "Rotary-Motion Feed-Through Apparatus", U.S. Pat. No. 4,629,219 to V. Balter (1986), entitled "Adjustable Connector Unit", and U.S. patent application Ser. No. 07/143,635, of V. Balter, filed Jan. 13, 1988 and entitled "Polar Coordinate Manipulator for Vacuum Application".